The present invention relates to a reagent and reagent kit for the measurement of fibrinogen and fibrin degradation products (FDP), and to a method for measurement of FDP.
When thrombi (stabilized fibrin) are formed in blood vessels or tissues due to hemostasis or other pathogenic causes, fibrinolysis is developed in vivo to remove the thrombi. The fibrinolysis for lysing thrombi is called secondary fibrinolysis in which fibrin in thrombi is degraded by enzymatic actions such as plasmin to produce fibrin degradation products (FbnDP: secondary fibrinolysis products) in blood. On the other hand, there is another fibrinolysis in vivo, called primary fibrinolysis, which is developed without association with formation of thrombi. During primary fibrinolysis, fibrinogen is degraded by enzymatic actions such as plasmin to produce fibrinogen degradation products (FbgDP: primary fibrinolysis products) in blood. These degradation products of fibrin and fibrinogen are collectively called as FDP (fibrinogen and fibrin degradation products).
The presence of FDP in blood can be an index for predicting in vivo hyperfibrinolysis. Due to this, the measurement of FDP in blood is used for diagnoses of diseases related to thrombi, cardiovascular disorders, hyperfibrinolysis, abnormal hemorrhage and the like or disseminated intravascular coagulation (DIC). Particularly, it is required to measure total FDP amount regardless of the type of FDP in order to classify pathological conditions of DIC.
Immunological approach has been conventionally applied for reagents for the measurement of blood FDP, and reagents utilizing turbidimetric immunoassay are commercially available, for example. Such reagents for the measurement of FDP include reagents using polyclonal antibodies such as anti-human fibrinogen antibodies. However, when FDP are measured with such reagents, the measured value of FDP may be falsely high unless a specimen to be measured is a biological sample of which fibrinogen has been deprived such as serum. However, the preparation of serum is complicated. In addition, because plasma is used as specimens for blood coagulation tests such as PT (prothrombin time), APTT (activated partial thromboplastin time), Fbg (fibrinogen concentration) and the like, reagents for the measurement of plasma FDP using monoclonal antibodies are clinically preferred in which plasma can be used as specimens (see Japanese Patent Publication Nos. Hei 5 (1993)-38906 and Hei 7 (1995)-46104, Japanese Patent No. 3472138 and Japanese Unexamined Patent Publication Nos. 2001-354700 and 2002-372536).